Targeting systems

ABSTRACT

Described herein is a method of controlling the operation of a missile launcher ( 12 ) by predicting the landing position ( 22 ) of a missile ( 16 ) in flight before it lands. The method includes tracking the missile ( 16 ) as it travels along its trajectory ( 18 ) until it reaches its apogee ( 20 ) and calculating the landing position ( 22 ) to provide a feedback correction signal to launcher ( 12 ) for the next missile to be launched. By utilising a feedback correction signal in this way, the time to hitting a target ( 10 ) from the time of engagement is substantially reduced.

The present invention relates to targeting systems and is more particularly concerned with a control system for such systems.

In conventional targeting systems, a shell is fired from a barrel towards a target and, depending on where the shell lands, the targeting system is adjusted to improve the accuracy of the position of where the next shell fired lands. This process is repeated until a shell hits the target and then no further adjustment is required as subsequent shells should be on target.

As the time to acquire an exact ‘lock’ on the target may be protracted, a number of shells may be wasted in the process of acquiring the range to hit the target. This has the consequence of reducing the overall life of the barrel from which the shell is fired.

It is therefore an object of the present invention to provide an improved targeting system which overcomes the disadvantages mentioned above.

In accordance with one aspect of the present invention, there is provided a method of controlling the operation of a missile launcher which fires free fall ballistics missiles, the method comprising the steps of:

-   a) firing a missile from the missile launcher; -   b) tracking the trajectory of the fired missile; -   c) calculating a predicted point of impact of the missile after it     reaches its trajectory apogee; -   d) feeding back the predicted point of impact to the missile     launcher before the missile impacts; -   e) applying a correction prior to firing a subsequent missile; and -   f) repeating steps a) to e) until the missile impacts a chosen     target.

Advantageously, step d) comprises feeding back the predicted range of the missile.

In accordance with a second aspect of the present invention, there is provided a control system for a free fall ballistics missile fired from a missile launcher, the control system including:—

-   -   tracking means for tracking the trajectory of a missile fired         from the missile launcher;     -   calculation means for calculating a predicted point of impact of         the missile, the calculation means being operable immediately         after the missile reaches its trajectory apogee; and     -   feedback means for feeding back the predicted point of impact to         the missile launcher so that a correction can be applied before         the fired missile makes impact prior to the launch of subsequent         missile.

Advantageously, the calculation means comprises a processor connected to receive data from the tracking means and to provide data relating to the predicted point of impact in the form of range information.

It is preferred that the processor includes the feedback means.

In one embodiment of the present invention, the tracking means comprises a tracking radar system which recognises the missile as it is fired from the missile launcher.

In accordance with a further aspect of the present invention, there is provided a targeting system including a control system as described above.

For a better understanding of the present invention, reference will now be made, by way of example only, to the accompanying drawings in which:—

FIG. 1 illustrates a missile launcher firing a missile towards a target in accordance with the present invention; and

FIG. 2 is a block diagram of a control system in accordance with present invention.

Referring initially to FIG. 1, a target 10 is shown being fired upon by a launcher system 12. For example, the target 10 may comprise a first ship and the launcher system 12 may be mounted on a platform located on land or on another ship. Only the barrel 14 of the launcher system 12 is shown for clarity.

When the target 10 is determined to be hostile and it is decided to fire on it, the launcher system 12 is positioned so that the barrel 14 is angled in position 14 a to fire a shell 16 a which follows a trajectory 18 a. The trajectory 18 a passes through an apogee 20 a before splashing down at 22 a and misses the ship 10.

In accordance with the present invention, a radar system (not shown) associated with the launcher system 12 tracks the shell 16 a as it exits barrel 14 a until it reaches the apogee 20 a of its trajectory. From the data collected by the radar system up to the apogee 20 a, it is possible to calculate the landing position 22 a before the shell 16 a reaches that position, and hence provide a range correction, ΔR₁, for the launcher system 12. This range correction effectively moves the barrel 14 to position 14 b ready to fire another shell 16 b before shell 16 a hits position 22 a.

Shell 16 b follows trajectory 18 b and has an apogee at 20 b. However, although landing position 22 b of shell 16 b is nearer the ship 10, a further range correction, ΔR₂, is required. As before, the further range correction is calculated before shell 16 b reaches landing position 22 b, and is applied to move the barrel 14 to position 14 c ready to fire a further shell 16 c before shell 16 b hits position 22 b.

Shell 16 c follows trajectory 18 c and has an apogee at 20 c. In this case, it is calculated that landing position 22 c of shell 16 c is coincidental with the ship 10 before shell 16 c reaches that position and at least one further shell (not shown) can be directed along substantially the same trajectory as trajectory 18 c to impact the ship 10.

Turning now to FIG. 2, a block diagram illustrating a control system 30 for launcher 12 of FIG. 1 is shown. The control system 30 comprises a target acquisition unit 32 which provides initial targeting instructions for a launcher control unit 34 which launches a shell 16 a from a barrel 14 (FIG. 1). The launcher control unit 34 is connected to a tracking radar unit 36 and a processor unit 38. The target acquisition unit 32 is also connected to tracking radar unit 36 and the processor unit 38 as shown.

When the target acquisition unit 32 provides the initial targeting instructions to the launcher control unit 34 via link 40, it provides the same instructions to the tracking radar unit 36 and the processor unit 38 via links 42 and 44 respectively. These instructions establish the starting point from which the tracking radar unit 36 provides data relating to the trajectory of a shell which is launched using those instructions, and from which the processor unit 38 calculates the range correction data for the launcher control unit 34.

The launcher control unit 34 provides data relating to the shell (not shown) which is to be launched by the launcher (not shown) to the tracking radar unit 36 over the link 46. This data provides the tracking radar unit 36 with details of how to recognise the shell which it is to track before or as the shell is launched. The launcher control unit 34 also provides data relating to launch of the shell to the processor unit 38 over link 48. Data from the tracking radar unit 36 is fed via link 50 to the processor unit 38, so that the processor unit 38 can calculate the predicted location of the shell impact once the apogee of the trajectory of the shell has been achieved, and provide range correction data for the launcher control unit 34 over link 52.

It will be appreciated that once the tracking radar unit 36 has established a settled track on a shell which has been launched from a launcher (not shown) associated with the launcher control unit 34, the data sent to the processor unit 38 from that settled track allows the predicted shell impact location to be determined with some accuracy. The accuracy of the predicted shell impact location will improve as a function of time, and it has been determined that a while after the shell has reached the apogee of its trajectory, the accuracy of the predicted shell impact location is adequate to use as the basis for a feedback signal for the launcher control unit 34 to correct the elevation of the barrel of the launcher. This has the advantage that the predicted range of the shell is known at a time considerably before the shell impacts and the launch control unit 34 can apply a correction to a second shell from a shell which is yet to land.

It will readily be understood that a filtering process can be used to provide a best estimate of the predicted shell impact location.

Moreover, the system of the present invention has the advantage that the number of shells which need to be fired in an engagement, from the start of the engagement to hitting the target, can be substantially reduced. The time involved is also reduced. This, in turn, has the advantage that barrel life of the launcher can be extended in proportion.

Although the present invention has been described with reference to determining the landing position of a shell, it will be understood that the invention can be applied to any free fall ballistics missile. Furthermore, the invention can be used with any stationary or relatively slowly-moving target. 

1. A method of controlling the operation of a missile launcher which fires free fall ballistics missiles, the method comprising the steps of: a) firing a missile from the missile launcher; b) tracking the trajectory of the fired missile; c) calculating a predicted point of impact of the missile after it reaches its trajectory apogee; d) feeding back the predicted point of impact to the missile launcher before the missile impacts; e) applying a correction prior to firing a subsequent missile; and f) repeating steps a) to e) until the missile impacts a chosen target.
 2. A method according to claim 1, wherein step d) comprises feeding back the predicted range of the missile.
 3. A control system for a free fall ballistics missile fired from a missile launcher, the control system including:— tracking means for tracking the trajectory of a missile fired from the missile launcher; calculation means for calculating a predicted point of impact of the missile, the calculation means being operable immediately after the missile reaches its trajectory apogee; and feedback means for feeding back the predicted point of impact to the missile launcher so that a correction can be applied before the fired missile makes impact prior to the launch of subsequent missile.
 4. A control system according to claim 3, wherein the calculation means comprises a processor connected to receive data from the tracking means and to provide data relating to the predicted point of impact in the form of range information.
 5. A control system according to claim 4, wherein the processor includes the feedback means.
 6. A control system according to claim 3, wherein the tracking means comprises a tracking radar system.
 7. A control system according to claim 6, wherein the tracking radar system recognises the missile as it is fired from the missile launcher. 8-10. (canceled)
 11. A control system according to claim 4, wherein the tracking means comprises a tracking radar system.
 12. A control system according to claim 11, wherein the tracking radar system recognizes the missile as it is fired from the missile launcher.
 13. A control system according to claim 5, wherein the tracking means comprises a tracking radar system.
 14. A control system according to claim 13, wherein the tracking radar system recognizes the missile as it is fired from the missile launcher.
 15. A targeting system including a control system according to claim
 3. 16. A targeting system including a control system according to claim
 7. 17. A targeting system including a control system according to claim
 12. 18. A targeting system including a control system according to claim
 14. 